Iowa Influenza Surveillance Network Final Report 2006-2008

Abstract

The Iowa Influenza Surveillance Network (IISN) tracks the overall activity, age groups impacted, outbreaks, type and strain, and severity of seasonal influenza. In the 2006-2007 season the network had more than 90 reporting sites that included physicians, clinics, hospitals, schools and long term care facilities (Appendix A). Other non-network reporters who contributed influenza data included medical clinics, hospitals, laboratories, local public health departments and neighboring state health departments. 010203040506070424548495051521234567891011121314MMWR weekNumber of cases2006-20072005-2006
The 2006-2007 influenza season in Iowa began earlier than any previously recorded data indicates, however, the season’s peak occurred much later in the season. In addition to early cases, this season was also unusual in that all three anticipated strains (AH1N1, AH3N2, and B) were reported by the first of December (Appendix B). The first laboratory-confirmed case in the 2005-2006 season was identified December 5, 2005; the first case for the 2006-2007 season was on November 2, 2006. The predominant strain for 2005-2006 was influenza AH3, but for 2006-2007 both influenza AH1 and B dominated influenza infections. However improvements in influenza specimen submission to the University Hygienic Laboratory may have also played a role in early detection and overall case detection.
In summary, all influenza activity indicators show a peak between the MMWR weeks 5 and 9 (i.e. February 14- March 4). Children from five years to eight years of age were impacted more than other age groups. There were few influenza hospitalizations and fatalities in all age groups.